Seipelä - Gold Database

Back to Gold map			Alphabetical list
Name	Seipelä	DATA UPDATED	24.5.2007
Alternative names
Deposit summary	SEIPELÄ, in the NE part of the Suomussalmi greenstone belt, is an Archaean orogenic gold occurrence with no resource estimate available. It is hosted by tholeiitic metabasalt and comprises auriferous quartz veins and altered host rock. The occurrence is controlled by shear zones parallel to the greenstone belt-granitoid contact.
LOCATION
Geological domain	Archaean	Belt	Suomussalmi
Site photo		Regional map
Map sheet	451303
Northing (kkj)	7240600	Easting (kkj)	4469850
Latitude	65.25993N	Longitude	29.35113E
Municipality	Suomussalmi
Nearest town, roads	47 km NE from Suomussalmi. One km from a sealed road, a gravel road across the area.
MINING
Exploration licence no	6550/1, 7633/2	Mining concession no
Present holder	Polar Mining (2003–)
Previous holders	Geological Survey of Finland (GTK) (1997–1999), Outokumpu Oyj (2002–2003)
Mine photo 1		Mine photo 2
Mine photo 3		Mine photo 4
Status of development	Prospect
When mined
Resources
Deposit size (Mt)		Reference (size)
Total in-situ gold (kg)		Reference (in-situ Au)
Total gold production (kg)		Reference (gold prod)
Production of other metals
Extent of mineralisation
Lodes
Best sections	1 m @ 1.33 ppm Au [1,7].
EXPLORATION
Discovery year	1998
Discovery	By GTK: the first indications were anomalous Au values in regional till geochemistry and quartz-, arsenopyrite- and tourmaline-rich rocks detected in outcrop in the region; the mineralisation was detected by diamond-drilling into an area with a distinct IP anomaly [1,7].
Exploration history	GTK (1995–1999) [1,7]: bedrock mapping, ground IP survey, till geochemical survey, diamond drilling.
Section figure 1		Plan figure 1
Section figure 2		Plan figure 2
Section figure 3		Plan figure 3
Trench fig 1		Trench fig 4
Trench fig 2		Trench fig 5
Trench fig 3		Trench fig 6
Explor site photo 1		Explor site photo 2
Geophysical response	The most intense IP anomalies are related to graphitic phyllite [7].
Drilling	GTK (1998): 12 diamond-drill holes, total 628 m [1].
Elements analysed	By ICP-AES: Ag, Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sc, Se, Si, Sr, Th, Ti, V, Y, Zn; by GAAS: Au Te [7].
Primary dispersion
Secondary dispersion	The Au and As anomalies in till are only partially explained by the mineralisation detected [1,7].
Primary anomaly fig 1		Secondary anomaly fig 1
Primary anomaly fig 2		Secondary anomaly fig 2
Primary anomaly fig 3		Secondary anomaly fig 3
Primary anomaly fig 4		Secondary anomaly fig 4
Primary anomaly fig 5		Secondary anomaly fig 5
Economic evaluations
Exploration geologist in charge	GTK: Kimmo Pietikäinen
ORE
Siting of gold
Fineness
Major opaques	Arsenopyrite, pyrrhotite [1,7]
Minor opaques
Gangue	Quartz, tourmaline, scheelite [1,7].
Ore miner. photo 1		Ore miner. photo 5
Ore miner. photo 2		Ore miner. photo 6
Ore miner. photo 3		Ore outcrop photo 1
Ore miner. photo 4		Ore outcrop photo 2
Ore composition
Enriched elements
Ore fluid
Stable isotopes
Pb isotope data
GEOLOGY
Geological setting	The deposit is in the western part of the Tormua Schist Belt which forms the NE part of the late Archaean Suomussalmi Greenstone Belt and is in the rocks of the 3.0–2.8 Ga Luoma Group of the greenstone belt [1,3,5].
Major host rocks	High-Mg metatholeiite [1].
Minor host rocks
Intrusives	TTG granitoids, from 2739±8 Ma to 2697±10 Ma of age, are abundant within and near the greenstone belt [2]. The hosting sequence is cut by pluton ranging from leucotonalite to granite and intruded by narrow granitic and more extensive dolerite dykes [1].
Regional geol map 1		Outcrop photo 1
Regional geol map 2		Outcrop photo 2
Local geology map 1		Outcrop photo 3
Local geology map 2
METAMORPHISM
Metamorphic history
Metamorphic grade	Amphibolite facies, at about 5 kbar and 600°C [2].
Metamorphic mineral assemblage
Metamorph photo 1		Metamorph photo 2
STRUCTURE
Structural style	Brittle-ductile [1]
Closest major shear
Controlling structure	Possibly, shear zones parallel to the greenstone belt-granitoid contact [1,7].
Deformation history	At least, four deformation stages during the late Archaean and two deformation stages during the Palaeoproterozoic time detected in the area; gold mineralisation is related to the Archaean late-D3 stage [2,3,4]. Age of D2 is probably 2820±15 Ma [7] or 2843±18 Ma [8]. Syn-D3 granodiorite suggests an age of ca. 2718 Ma for the peak of the D3 stage [7].
Ore fabric
Veins	Early sugary and later clear quartz veins, postdated by arsenopyrite-tourmaline bearing quartz veins [1,7].
Structure photo 1		Vein photo 1
Structure photo 2		Vein photo 2
Structure photo 3		Vein photo 3
ALTERATION
General alteration	Sericitisation, carbonation [1].
Proximal alteration
Intermediate alteration
Distal alteration
Zonation figure		Prox alteration photo 1
Alteration photo 1		Prox alteration photo 2
Alteration photo 2		Intermed alteration photo
Alteration photo 3		Distal alteration photo 1
Post-mineralisation modifications	Post-mineralisation D4 deformation [5].
TIMING	During ca. 2720–2650 Ma [7].
GENETIC MODEL	Clearly epigenetic, "mesothermal" mineralisation with a distinct structural control [1], formed during late-Archaean cratonisation [6].
GENETIC TYPE	Orogenic	References	[6]
Alternative genetic type 1		References
Alternative genetic type 2		References
References 1. Pietikäinen, K. & Niskanen, M. 2001. Tutkimustyöselostus Suomussalmen kunnan Saarikylässä sijaitsevista valtauksista Seipelä 1 (Kaiv.RN:o 6550/1) ja Siikaselänne 1 (Kaiv.RN:o 5620/1) sekä niitä ympäröivistä valtausvarausalueesta (69/1997). English summary: A research report of studies concenrning the claims of Seipelä 1, Siikaselänne 1 and the surrounding are reserved for a claim (register numbers of claims: 6550/1, 5620/1 and 69/1997, respectively), located in the village of Härmänkylä, Kuhmo, estern Finland. Geol. Surv. Finland, Report M 06/4513/2001/2. 9 p. (3.9 MB) 2. Luukkonen, E., Pajunen, M. & Poutiainen, M. 1992. Kuhmo-Suomussalmen alueen arkeeisen kallioperän rakenne-evoluutio ja Au-aiheet. In: E. Ekdahl (ed.) Suomen kallioperän kehitys ja raaka-ainevarat. Vuorimiesyhdistys, Sarja B, 51, 11–12. 3. Luukkonen, E. 1992. Late Archaean and Early Proterozoic structural evolution in the Kuhmo-Suomussalmi Terrain, eastern Finland. Annales universitatis Turkuensis. Ser. A. II 78, 1–37. 4. Sorjonen-Ward, P., Nironen, M. & Luukkonen, E. 1997. Greenstone associations in Finland. In: M. J. de Wit and L. D. Ashwal (eds) Greenstone Belts. Clarendon Press, Oxford. 677–6 98. 5. Luukkonen, E. (ed.) 1998. Suomussalmen, Kuhmon ja Kostamuksen arkeeiset vihreäkivivyöhykkeet ja niihihn liittyvä malminmuodostus. Ekskursio-opas. Vuorimiesyhdistys, Sarja B, No 66, 40 p. (in Finnish) 6. Papunen, H., Halkoaho, T., Liimatainen, J. & Luukkonen, E. 2001. Metallogeny of the Archaean Tipasjärvi-Kuhmo-Suomussalmi greenstone belt, Finland. AGSO – Geoscience Australia, Record 2001/37, 456–458. 7. Luukkonen, E., Halkoaho, T., Hartikainen, A., Heino, T., Niskanen, M., Pietikäinen, K. & Tenhola, M. 2002. Itä-Suomen arkeeiset alueet -hankkeen (12201 ja 210 5000) toiminta vuosina 1992–2001 Suomussalmen, Hyrynsalmen, Kuhmon, Nurmeksen, Rautavaaran, Valtimon, Lieksan, Ilomantsin, Kiihtelysvaaran, Enon, Kontiolahden, Tohmajärven ja Tuupovaaran alueella. Geol. Surv. Finland, Report M19/4513/2002/1. 265 p. (in Finnish, 130 MB) 8. Sorjonen-Ward, P. & Luukkonen, E.J. 2005. Archean rocks. In: Precambrian Geology of Finland – Key to the Evolution of The Fennoscandian Shield. Elsevier Science B.V., Amsterdam, 19–9 9. 9. Goode, K. 2004. Dragon Mining NL (DRA) – Bringing Scandinavian Gold Mines into Production. 12 p. (938 KB)
Back to Gold map			Alphabetical list